Literary usage of Ardency

Below you will find example usage of this term as found in modern and/or classical literature:

1.A Manual of Naval Architecture: For the Use of Officers of the Royal Navy by William Henry White (1882)"Some vessels, however, are not so well arranged for sailing purposes, and in
them "ardency" or "slackness" when sailing on a wind may be practically ..."

2.A Manual of Naval Architecture for Use of Officers of the Royal Navy by Sir William Henry White (1900)"Some vessels, however, are not so well arranged for sailing purposes, and in
them " ardency " or " slackness " when sailing on a wind may be practically ..."